Tautonyms: Highest was only 7272 = (2-4)^9 + (7-1)^5 + (8-6)^3; lowest was only -7272 = (1-7)^5 + (2-4)^3 + (8-6)^9. Of note, no results came up for -1010 this time, although I did find that -1919 = (1-4)^7 + (3-8)^2 + (9-6)^5 -- so a less negative result is still possible.